Abstract：
Inflammatory pseudotumor (IPT) is a rare benign mass characterized by infiltration of inflammatory cells and proliferation of fibrous tissues. Consistent with increasing knowledge about IgG4-related disease (RD), it has been implicated in the etiology of hepatic IPT, which is pathologically classified into two categories with respect to the proportion of IgG4-positive plasma cells: fibrohistiocytic- and lymphoplasmacytic-type. A 66-year-old man was admitted for treatment of cholecystocholangitis. Incidentally, abdominal computed tomography (CT) revealed an ambiguous low-density mass within segment 4 (S4) of the liver. Magnetic resonance imaging (MRI) showed the typical images of hepatic IPT within S4. Together with CT and MRI imaging, we suspected hepatic IPT, and had the opportunity to biopsy the S4 lesion during surgery for cholecystitis. Histopathological examination of liver tissue showed diffuse fibrous tissues, dense lymphoplasmacytic infiltration, and obliterative phlebitis with no evidence of malignancy. Despite infiltration of IgG4-positive plasma cells, these histological findings corresponded with fibrohistiocytic-type hepatic IPT. Similarly, in the resected gallbladder, relatively abundant IgG4-positive cells were observed, but not entirely consistent with IgG4-RD criteria. Although IgG4 immunostaining can be useful for the classification of hepatic IPT, the present histological tissues were borderline condition defined by IgG4-RD criteria. This rare case of hepatic IPT suggests a future focus on the borderline histological features of IgG4-RD.
摘要：
炎性假瘤（IPT）是一种罕见的良性肿块，其特征是炎性细胞浸润和纤维组织增殖。与越来越多的关于IgG4相关疾病（RD）的知识一致，它与肝IPT的病因有关，根据IgG4阳性浆细胞的比例，在病理上分为两类：纤维组织细胞型和淋巴浆细胞型。一名66岁的男子因治疗胆囊性胆管炎而入院。顺便说一句,腹部计算机断层扫描（CT）显示肝脏第4段（S4）内有一个模糊的低密度肿块。磁共振成像（MRI）显示S4内肝脏IPT的典型图像。加上CT和MRI成像，我们怀疑肝脏IPT,并有机会在胆囊炎手术期间对S4病变进行活检。肝组织病理学检查显示弥漫性纤维组织，密集的淋巴浆细胞浸润，和闭塞性静脉炎，没有恶性肿瘤的证据。尽管有IgG4阳性浆细胞浸润，这些组织学发现与纤维组织细胞型肝IPT相对应.同样，在切除的胆囊中，观察到相对丰富的IgG4阳性细胞，但不完全符合IgG4-RD标准。尽管IgG4免疫染色可用于肝脏IPT的分类，目前的组织学组织为IgG4-RD标准定义的临界条件.这种罕见的肝IPT病例表明未来将重点放在IgG4-RD的临界组织学特征上。
